Junction box



Q 7, v1950 I H. L. BUSH ,529,133

JUNCTION Box I Filed Oct. 1, 1947 I 2 Sheets-Sheet 2 N VEN TOR.

Patented Nov. 7, 1950 JUNCTION BOX Harold L. Bush, North Syracuse, N.Y., assignor to Grouse-Hinds Company, Syracuse, N. Y., a corporation ofNew York Application October 1, 1947., Serial No. 777,219

Claims.

This invention has to do with a junction box for electrical conductorsand particularly an explosion proof junction box wherein branch circuitconductors are taken off from feed circuit conductors, the latterconsisting of conductors of unusually large cross section.

The invention has as an object a junction box ofthe type referred toembodying a structure whereby'the branch circuit conductors can bequickly and conveniently connected to the heavy feed circuit conductors,the connector terminals being readily adapted for various sizes ofconductors,,both on the branch and feed circuits.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed,

In describing this invention, reference is had to the accompanyingdrawings in which like characters designate corresponding parts in allthe views.

Figure 1 is a vertical sectional view of a junction box embodying myinvention.

Figure 2 is a top plan view of the structure shown in Figure 1 with theclosure cap removed and a portion of the top insulating shield brokenaway.

Figure 3 is a top plan view of one of the feed conductor terminalblocks.

The invention consists of a metallic housing 9 formed with aperturedhubs III, II, to receive conduits enclosing the conductors. The housingis provided with an opening in the top wall thereof which, in thestructure illustrated in the drawings, is commensurate in size to theinterior of the housing 9. In this case, the housing is of cylindricalform, and the opening is internally threaded to receive an invertedcup-shaped closure cap I2 which, when threaded into the opening, forms aflame tight closure for the opening.

A plurality of feed conductor terminal blocks I3 are mounted in thehousing on the base wall I4 thereof, the blocks being mounted upon aninsulating panel I5 secured to the bottom wall of the housing, as byscrews I6, and the blocks I3 are secured to the panel in either one oftwo positions by screws I'I shown in dotted outline, Figure 1. Theblocks I3 are formed with a transversely extending rectangular grooveI8, and with a groove I9 of V formation extending at right angles to thegroove I8. The corner portions of the blocks are provided with threadedapertures to receive the mounting screws IT.

A terminal bar 22 is mounted upon each of the blocks I3 and extendsupwardly therefrom and outwardly through the opening in the top of thehousing. The lower end of each of the bars 22 is formed with a jawportion 24 adapted to be positioned in the grooves I8, I9, the barsbeing detachably secured to the blocks by tightening means in the formof screws 26 which also thread into the apertures 20 of the blocks I3.The jaws 24, in conjunction with the blocks I3 and the tightening means26, form a clamp for clamping the large feed conductors 28. Branchconductor terminals 29 are mounted upon opposite sides of the bars 22 onthe outwardly extending portions thereof.

With this arrangement, the housing is mounted upon the wall, or othersurface, by bolts, lag

screws, or the like, extending through apertured' feet SI. The conduitlines are attached to the hubs I0, II, and the conductors pulled throughthe conduits.

The feed conductors 28 are of large size rang-, ing from 1/0 to 500circular mills. To connect these heavy conductors, it is only necessaryto de-insulate a short portion of each conductor and drop it into one ofthe connector blocks I3. The terminal bars 22 are then secured to theblocks respectively, and this operation results in the heavy conductorbeing clamped between the block and its associated connector bar 22.

The branch circuit conductors may be then conveniently attached to theterminals 29 inasmuch as they are fully exposed outside of the housing.These branch conductors may range in size from No. 14 Wire to 4/0 wire.However, there is no difficulty in connecting the larger size branchconductors inasmuch as the branch connectors are positioned outside ofthe housing and the workman is in no way hampered, or obstructed, inmaking the connections. After the branch circuit conductors have beenattached to the terminals 29, the closure cap I2 is screwed intoposition.

An insulating plate 36 may be detachably mounted over the ends of theterminal bars 22. As shown, blocks 31 of insulating material aredetachably secured to the two outer terminal bars, as by screws 38, andthe top plate 36 secured to the blocks 31, as by screws 40. Shields 4Imay be mounted on the under side of the plate 36 to effectively preventany arcing or short circuit between the terminal bars and likewise, a U-shaped shield 43 may be employed in connection with the mounting of oneor more of the blocks I3.

In Figure 1, the left and center terminal block I 3 is positioned toreceive the feed conductors 28 in the V slots I9. The right hand blockis positioned to receive the conductor in the rectangular slot l8. Thisslot is to accommodate conductors of the smaller sizes, while the slots19 accommodate conductors of larger size.

What I claim is:

1. An explosion proof junction box for electrical conductors comprisinga housing formed with conduit receiving apertures and having an openingin the top wall, a plurality of feed conductor terminal blocks mountedin the housing on the bottom wall thereof, a terminal bar detachablysecured to each of said terminal blocks and extending outwardly throughsaid opening, the lower ends of said bars being cooperable with saidterminal blocks respectively to clamp conductors thereto, branchterminal connectors carried on the outer ends of said bars, and aclosure cap enclosing the outwardly extending portions of said bars andforming a flame tight/closure for said opening.

trical conductors comprising a housing for con- 4 ing position, aclosure cap enclosing the outwardly extending portion of said bars andforming a flame tight closure for said opening.

4. An explosion proof junction box for electrical conductors comprisinga housing formed With conduit receiving apertures and having an openingin the top wall, a plurality of feed'conductor terminal blocks mountedin the housing on the bottom wall thereof, a terminal bar extendingoutwardly from each of said blocks through said opening and beingprovided at its outer end with branch terminal connectors, each of saidbars having a jaw member which, in conjunction with its associatedterminal block and tightening means, forms a clamp for a feed conductor,a closure cap enclosing the outer porduit receiving apertures and havingan opening in the top wall, a plurality of terminal blocks mounted inthe housing on the bottom wall thereof, a terminal bar extendingoutwardly from each of said blocks through said opening, and said barsbeing provided at their outer ends with branch terminal connectors, thelower ends of s'aid'terminal bars and said blocks forming conductorclamp jaws, means operable to detachably secure the terminal bars tosaid blocks respectively, and. to contract said clamp jaws on aconductor, a closure cap enclosing the outwardly extending portions ofsaid bars and forming a flame tightjclosure for said opening.

v 3. An explosion proof junction box for electrical conductorscomprising a housing formed with conduitjreceiving apertures and havingan opening in the top wall thereof, a plurality offeedcondu'ctorterminal blocks mounted in the housing on the bottom wall thereof, aterminal bar extending outwardly from each of said blocks through saidopening and being provided at their outer ends with branch terminalconnectors, the lower end of each terminal bar having a jaw membercooperable with said block in one relation, to form a clamp for a feedconductor, and in another relation to form a clamp for a conductor ofdifferent size, means operable to detachably secure the terminal bars tosaid blocks respectively, and to move said jaw into conductor clamptionof said bars and forming a flame tight closure for said opening.

5. An explosion proof junction box for electrical conductors comprisinga housing formed with conduit receiving apertures and having an opening'in the top wall thereof substantially commensurate with the interior ofthe housing; a plurality of U-shaped terminal blocks mounted in thehousing on the bottom wall thereof, a branch terminal bar extendingoutwardly from each of said blocks through said opening and beingprovided at its outer end with branch ter-' minal connectors, each ofsaid terminal bars being formed at its lower end with a conductor clampjaw mounted between the leg portions of said U shaped terminal block,means operableto detachabl'y' secure the terminal bar to the block andto cause said jaw to clamp a feed conductor to the block, a closure capenclosing the upwardly extending portions of said terminal bars andforming. a flame tight closure for said opening.

HAROLD L. BUSH. f

REFERENCES CITED The following references are of record in the flle ofthis patent:

UNITED STATES PATENTS Number Name Date 2,208,558 Appleton July 23, 1940FOREIGN PATENTS Number Country Date 2 Great Britain Nov. 25, L899 WWW.

